1. Field Of The Invention
The present invention generally relates to a system for providing temporary access to a closed container, and more particularly to an automatic sampler system which provides a temporary opening in the resealable closure of a sample container.
2. Description Of The Prior Art
The prior art provides a number of automatic sampling systems. Generally, these systems receive sample containers, remove a predetermined quantity of sample from each container at a first location, and transfer the removed sample to a second location for analysis. The sample containers usually used with these systems are open-top vials or tubes transported in the system on carousels and transferred between carousels with mechanical push arms or other similar devices.
Samples to be tested in automated sampling systems are most often collected in evacuated containers. These containers generally comprise glass tubes closed with rubber stoppers and sealed with a vacuum. The sample displaces part of the vacuum; but some vacuum may remain. Removal of the stopper may result in the formation of aerosol particles. Consequently, when an operator removes the stopper before placing the container in the automated system, the aerosol spray may expose the operator to any harmful substances contained in the sample. In addition, removal of the stopper manually by the operator increases the cost of operation and decreases the efficiency and reliability of an automated system.
Using open sample containers in an automatic sampling system presents a number of problems. First, the various forces which move the containers through the system cause spills and contamination. Second, open sample containers expose an operator to any harmful substances disposed in the containers. Finally, because open containers require special care, the cost of operation increases.
One solution to these problems is to use closed containers in the automated system. However, most prior systems require the use of open containers. One known automated sampling system (disclosed in U.S. Pat. No. 4,478,095 to Bradley et al.) provides sampling through the stopper of a closed vial. However, to do so, this system includes a complex arrangement of needles, purge mechanisms, and other assemblies. It uses gas pressurization and other complex techniques to take samples from sealed sample containers.
The automated sampling system of the present invention avoids the problems outlined above. The system provides a temporary opening in the closure of a closed sample container in a quick and efficient manner. It allows the system to perform many testing operations through the temporary opening without having to close and reopen the closure. It is a simple, fully automated system which minimizes the expense of manufacture and assembly and gives precise, uniform and reliable performance. This system produces the requisite mechanical action to temporarily open the closure of a sample container and quickly and efficiently establish access to the inside of the container.